Art of manufacturing square-bottom paper bags.



No. 689,422. Patented Dec. 24, l00l. C. F. SCHMELZ.

ART OF MANUFACTURING SQUARE BOTTOM PAPER BAGS. (Appliution filed 1m. 19,1901.) (No Model.) 2 Shuts-Sheet I.

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CHARLES F. SCI-IMELZ, OF HARTFORD, CONNECTICUT, ASSIGNOR TO UNION PAPERBAG MACHINE COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OFPENNSYLVANIA.-

ART OF MANUFACTURING SQUARE-BOTTOM PAPER BAGS.

. SPECIFICATION forming part of Letters Patent No. 689,422, datedDecember 24, 1901.

Application filed March 19, 1901. Serial No. 51,826. (No model.)

To all whom it may concern:

Be it known that I, CHARLES F. SoHMELz,

a citizen of the United States of America,

and aresident of Hartford, Connecticut, have invented certain new anduseful Improvements in the Art of Manufacturing Square- Bottom PaperBags, of which the following is a specification.

This invention relates to the art, of manufacturing square-bottom paperbags; and it has for its object an improved method of forming theso-called diamond fold in a bellows-sided or tucked tube or blank, suchmethod being adapted for use in connection with any well-known methodsof forming the tube and of subsequently pasting and folding the diamondto complete the bag.

My invention has more particularly for its object the improved method ofopening out the open or bottom-forming end of the blank,

so as to form the inside triangular folds in an easy and rapid manner,and it comprises as one of its features the manipulation of the plies ofthe blank between certain points thereof. The several instrumentalitiesfor holding said plies are caused to engage the same at points thedistance of whichfrom the bottom-defining line is equal to the depth ofthe tucks, the blank being opened out by and between theseinstrumentalities around a primary folding-line which is disposedbetween said points of engagement and the bottomdefining line, and whensaid points of engagement have arrived at positions at opposite sides ofthis primary folding-line the distance between the points of engagementis increased until the sides will have been fully stretched out betweensaid points.

One of the ordinary methods of forming the diamond on a bag-blankcomprises the engagement of the upper and lower plies thereof bysuitable devices generally known as tuck and box holders, these devicesengaging said plies at certain distances from the bottom-defining line,so that when the tucked sides are gradually straightened or stretchedout by and between said devices the inside triangular folds will befully de= veloped. The process of straightening out or stretching thetucked sides is usually carried 'out by swinging the devices whichengage one ply of the blank away from those engaging the other ply andsubstantially around the defining-line as an axis, the distance fromeach of said devices to the defining-line remaining. substantiallyuniform throughout this folding operation. In my improved method theplies of the blank are manipulated in such a manner that the tuckedsides will have been distended but partially between the points ofengagement even after the latter have arrived at positions at oppositesides of the primary folding-line, so that'subsequently the distancebetween such points must be increased in order fully to stretch out thetucked sides of the tube.

A process incorporating my invention is clearly illustrated in theaccompanying draw ings, in which- Figure 1 is a side view of abag-blank, illustrating the manner in which the upper and lower pliesthereof are engaged by the folding instrumentalities. Fig. 2 is a topview of Fig. 1. Fig. 3 is an end View of the blank. Fig. tshows theupper ply of the blank folded over around the primary folding-line. Fig.5 is a top view thereof. Figs. 6 and 7 show a further advancement in thetube-distending operation; and Figs. 8 and 9 show a side and top View,respectively, of the blank when the folders have arrived at their finalpositions and the diamond is substantially completed.

In the drawings the blank 10 is shown having tucked or bellows sides 11and comprising a bag-forming section A and the bottom= formingIsectionA, the boundary-line between said sections being generally known as thedefining-line and indicated in the present instance by d 01. Referringto Figs. 1 and 2, the upper ply 12 of the blank is shown engaged by theso-called box-holders B and the proper function of which is to fold saidply around the edgefof a member B, which constitutes a folding membercooperative with the box-holders B. The blank 10 is properly positionedrelatively to the various folding instrumentalities, so that the memberB will be disposed above the upper ply, while the box-holders B and thetuck-holders T will enter the tucks and the cooperative member T will bedisposed below the lower ply 13 of the blank, and the frontdiamond-holder H will engage the same in the manner clearly shown inFig. 1. In order to insure the proper engagement of the upper ply of theblank by the box-holders B, the member B may now be turned forward inthe direction of arrow at and around the edgefuntil the upper ply isfirmly clamped between the box-holders B B and said member B, whereuponsaid member, and with it the box-holders, may be swung back again untilthe position shown in Figs. 4 and 5 has been reached, in which theprimary folding-line is formed by said edge f. At this time the tuckedsides have been partially distended between the points 20 and 21, whichconstitute the engaging points of the box and tuck holders,respectively. The distance between said points will now be increased,passing in its progress the condition shown in Fig. 6, which illustratesing the distance between the points 20 and 21 somewhat greater than thatbetween the points 20 and 21 of Fig. 4. On a further increase of thedistance between said points to the position shown in Fig. 8 the tuckedsides will be fully distended or stretched out be tween the points 20and 21", and the diamond may now be flattened and completed.

From the foregoing it will be seen that while the edge f of the member Bserves at first as a member around which the upper ply of the blank isfolded over, and to insure both sides of the upper ply being gripped inproper alinement with each other, said edge f will cease to be a foldingedge as soon as the dis tance between the box-holders B B and thetuck-holders T T is increased, so that the fold, which finallyculminates into the crossfold line of the bag-bottom, is in reality arunning fold which progresses at half the speed compared with theincrease in distance between the box-holders and tuck-holders. Themember T is in this instance the movable member and supports the frontdiamond: holder H, while the member B remains stationary. It is ofcourse understood that it is immaterial to the proper manipulation ofser es the blank in accordance with my improved method which one of saidmembers is stationary or movable relatively to the other so long as thedistance between the tuck-holders and box-holders is increased.

lVhile under ordinary conditions it is not deemed essential that therunning fold should be in any way supported, yet in some instances,particularly with a heavier weight of paper, any proper support andguidance for said running fold may be advantageously employed.Furthermore, it is considered that for the purpose of properly carryingout my improved method it is not essential that the member B or the edgefshould extend entirely across the bag-blank, although this constructionis preferable in some instances.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is

1. The improvement in the art of forming the diamond on bellows-sidedtubing, which consists in the engagement of the sides of the upper andlower tube-plies at. points, the distance of which from the primaryfolding-line is less than the depth of the tucks, folding over onetube-ply substantially around the folding-line as an axis and until thepoints of engagement are brought to positions at opposite sides ofsaidline, and subsequently separating said points to distend the tuckedsides completely between said points and to develop the insidetriangular folds, and subsequently completing the diamond.

2. The improved method of forming adiamond in square-bottom paper bagsfrom bellows-sided tubing, which consists in engaging the upper andlower plies at points, the dis tance of which from the bottom-definingline is equal to the depth of the tucks; completely folding one ply overand on a primary folding-line located between the points of engagementand the bottom-defining line, and subsequently increasing the distancebetween said points of engagement until the tucked sides have been fullystretched out between said points, and then completing the diamond. Y

CHAS. F. SOHMELZ.

Witnesses:

WM. H. HONISS, NELLIE PHOENIX.

